Deflection clamp

ABSTRACT

An edge chipper chips waney edges of a flitch of timber having parallel top and bottom sides, the flitch passing through feed roll pairs extends outward as a cantilever as it moves towards revolving chipper knives. Since depth trimmed by each chipper head differs in a random manner, an unbalanced force produced by the chipper heads tends to deflect the flitch - particularly before it reaches the outfeed rolls. This unbalanced force causes a deflection, producing a cant, chipped side edges of which can depart from desired dimensions by an intolerable amount. A deflection clamp bearing on the upper and lower sides of the flitch is provided, a pressure shoe of the clamp urges the flitch against a fixed anvil with ridges of the clamp and anvil forming grooves acting as tracks restraining the flitch against deflection. Passage of the flitch through the infeed roll pair senses flitch thickness and sets the clamp, and succeeding roll pairs, so as to lift by an adjustably determinate amount when reached by the moving flitch. Lift of the pressure shoe and of suceeding pressure rolls is resiliently resisted by a force which can be adjusted as required. Thus passage of the flitch through the feed roll pair automatically senses thickness and passes this information to the pressure shoe and succeeding pressure rolls for effective drive and restraint from deflection.

United States Patent [151 3,680,611 Mitten et al. [4 1 Aug. 1, 1972 541 DEFLECTION CLAMP 571 ABSTRACT [58] Field of Search ..144/162, 117 B, 242 A, 39, 144/41, 3 P, 172, 176, 117, 246, 246 C, 246

[56] References Cited UNITED STATES PATENTS 3,323,565 6/1967 Pease ..144/162 X 2,659,396 11/1953 Gledhill et a1 ..144/162 X 3,487,866 l/1970 Mitten ..144/162 X Primary ExaminerDonald R. Schran AttorneyBrian J. Wood An edge chipper chips waney edges of a flitch of timber having parallel top and bottom sides, the flitch passing through feed roll pairs extends outward as a cantilever as it moves towards revolving chipper knives. Since depth trimmed by each chipper head differs in a random manner, an unbalanced force produced by the chipper heads tends to deflect the flitch particularly before it reaches the outfeed rolls. This unbalanced force causes a deflection, producing a cant, chipped side edges of which can depart from desired dimensions by an intolerable amount. A deflection clamp bearing on the upper and lower sides of the flitch is provided, a pressure shoe of the clamp urges the flitch against a fixed anvil with ridges of the clamp and anvil forming grooves acting as tracks restraining the flitch against deflection.

Passage of the flitch through the infeed roll pair senses flitch thickness and sets the clamp, and succeeding roll pairs, so as to lift by an adjustably determinate amount when reached by the moving flitch. Lift of the pressure shoe and of suceeding pressure rolls is resiliently resisted by a force which can be adjusted as required. Thus passage of the flitch through the feed roll pair automatically senses thickness and passes this information to the pressure shoe and succeeding pressure rolls for effective drive and restraint from deflection.

9 Claims, 16 Drawing Figures 5 a r l "T -rig iil PATENTEDAus' 1 I972 3.680.611

' SHEI10F5 Robert pman and.

Leona d ten, Im'miturs PATENTED M 1 I972 SHEEI [1F 5 minnow: H912 3.680.611

SHEET 5 BF 5 Robert E. Chapman anc Leon. l'iltten I 1 GT5 2 DEFLECTION CLAMP BACKGROUND OF THE INVENTION 1 Field of the Invention The invention relates to a deflection clamp particularly but not exclusively for an edge chipper to efiect essentially straight line longitudinal passage of a waney flitch therethrough, together with feed roll structure including sensing means responsive to flitch thickness.

2. Prior Art Hereinafter a piece of lumber with waney or irregular opposite side edges is referred to as a flitch. In passing a flitch through an edge chipper so as to trim to a desired dimension, it is clear that different depths of cut appear at each edge, and furthermore that'there is random variation in depth of cut as the flitch passes through the edger. Because of the difference in the depth of cut on each side, a varying unbalanced reaction from unequal cutter forces arises, thistends to deflect the flitch laterally so that the trimmed edges are out of true because of irregular lateral movement, unless means are provided to ensure that travel of the flitch through the edger is straight line longitudinal translation within a tolerance set by permissable tolerance in lateral dimension of the trimmedflitch, hereinafter a cant.

Commonly, drive through the edger is accomplished by means including pressure rolls bearing upon upper and lower faces of the flitch, with means to apply pressure between the rolls so as to accomplish drive. The present invention is directed to minimizing lateral motion which arises, as explained, from the varying unbalanced cutter forces. The problem is well known, and in some known structures material reduction in lateral movement is effected.

U.S. Pat. No. 1,602,041 issued to Joseph A. Neal in 1926 teachesmeans for supporting and guiding material or stock passing through a resaw machine. Neals ingenious hold down structurehas not, so far as the present inventors are aware, been successfully adapted to deal with a flitch having opposite waney edges.

U.S. Pat. No. 2,254,501 issued to Solem in 1941 teaches a rubber cushion resilient roller particularly designed for use in multiple in building up section feed rolls for wood working machines.

Chippers having a resilient auxilliary pressure roll, for instance a rubber tired wheel, directed to reduce the lateral movement are also known, and have had some success. Resilient rolls, however, have disadvantages well known to those skilled in the art.

SUMMARY OF THE INVENTION The present invention provides a stationary anvil and a pressure shoe bearing on the flitch before it enters the chipper, the flitch passing between the anvil and the shoe. Both the pressure shoe and the anvil have raised longitudinal guide vanes, or ridges. The anvil being stationary, and the flitch being interposed between the anvil and the shoe, means are provided strongly to urge the shoe against the flitch so that depressions are formed in the flitch with the depressions being effectively tracks guiding the flitch longitudinally through the chipper without material transverse deflection. The flitch being resilient, provided that the urging force is not too great the depressions disappear, or nearly disappear, from the flitch when it has passed through the shoe and anvil. Parameter determining pressure isthat it be ofsuch magnitude,;depending uponithe particular wood of the'flitch, and magnitude of the wanieness which magnitude is directly 'relatedto the irregular unbalanced force as to restrain the flitch in the required longitudinal travel. If the .edged flitch, ie the cant, is to be a rough timber, any depression remaining is not of material consequence. If the cant is to be finished any residual track is readily removed in dressing to finished size.

A combination including the'pressure shoe and the anvil is hereinafter referredto as a deflection clamp.

The present inventionalso teaches means responsive to entry of the flitch between a firstfeed roll pair automatically to'place a seceeding roll pair (or pairs), and the pressure 'shoe,.in a determinate position for effective drive and restraint-sensing of thickness of the flitch being effected by entry between the first roll pair.

A detailed description following related to drawings gives exemplification of embodiment of the invention which, however, can be expressed in structure and mechanism other than that particularly. described and illustrated.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of an edge chipper. including structure according to the present invention,

FIG. l-A is a fragmented plan of a flitch,

FIG.J2 is a fragmented plan of the flitch,

FIG. 3 is an end elevation of the flitch as seen from 3--3 FIG. l-A,

FIG. 4 is a diagram showing a pressure shoe and an anvil of a deflection clamp according to the present invention, being means to effect longitudinaltravel of the flitch through the edge chipper,

FIG. 5 is a perspective of a frame of the edge chipper with the clamp, pressure rolls, and linkage of depth sensing and pressure mechanism, assembled to the frame, many parts of the chipper being omitted for clarity of illustration,

FIG. 6 is a diagram to illustrate action of the sensing and pressure mechanism, thediagram representing the mechanism as seen from-VL-VI FIG. 5,

FIG. 7 is a diagram illustrating unbalanced cutter force,

'FIG. 7-A is a scale smallerthan that of FIG. 6, illustrates cantilever effect, v

FIG. 8 is a perspective of an edge chipper showing pneumatic resilient means of the sensing and pressure mechanism,

FIG. 9 is a detail elevation of the pressure shoe,

FIG. 10 is a detail elevation of a curved shoe element,

FIG. 11, which is at a scale larger than that of FIG. 10, is a detail of a ridge of the curved shoe element,

FIG. 12 is a detail side elevation of the anvil,

FIG. 13 is a partly sectioned end elevation of the anvil,

FIG. 14 is a fragmented detail section showing a ridge of the anvil.

DETAILED DESCRIPTION FIG. I

An edge chipper 6 shown in side elevation in FIG. 1 includes a deflection clamp assembly 7 and feed roll and clamp linkage 8. An arrow 9 indicates direction of travel of a flitch 10, shown in broken outline, as it passes through the chipper being edged to form a cant. FIGS. 1 A, 2, 3

The flitch 10 hasoppcsite waney edges 11 and 12, an upper side 13, and a lower side 14. The upper and lower sides have been sawn and are considered as having parallel plane surfaces. A feed roll pair, FIG. 3, has an upper pressure roll 15 and a lower roll 16, the rolls havingaxes 15.1 and 16.1 respectively. An axis of travel of the flitch through the edger is designated 17,

considered to be horizontal.

Referring now to FIG. 3 the rolls rotate about the axes'15.1 and 16.1, which are horizontal and parallel in a (vertical) plane normal to the axis of travel. The axis 16.1 is fixed, with the axis of 15.1 of the upper feed roll spaced from the axis 16.1 as seen in FIG. 3. The upper and lower feed rolls bear respectively against the upper and lower sides 13, 14, of the flitch, a downward force as indicated by an arrow 19 is applied to the upper roll so that, one roll of the pair being driven, the flitch travels in the direction 9 moving towards opposed rotating knives of the edge chipper, not here shown. Additional roll pairs are provided, as is later described.

Thus when a roll of a pair is driven the flitch moves in the direction 9 and is edged to form a cant 21 shown in broken outline, the cant having parallel side edges 22 and23.

IN FIG. 3 a vertical plane containing the axis 17 is designated 24. The edge chipper heads (not shown) have parallel axes 25 and 26 which can be vertical, the axes being spaced at such distance as is required to form the side edges 22 and 23. The present invention provides structure and mechanism directed to eflect that the cant side edges 22 and 23 are parallel to the plane 24 within limits of dimensional tolerance of the cant.

The'flitch is considered as having a central longitudinal axis, and the cant has a longitudinal axis. It is seen that if the longitudinal axis of theflitch is coincident with the travel axis 17, the motion of the flitch axis is translation only within the limits above then the longitudinal axis of the cant is also coincident with the travel axis 17, the cant being rectangular. Motion restricted as above is hereinafter referred to as longitudinal on a common longitudinal axis, namely the axis 17.

FIG. 4

Means to accomplish the foregoing include the deflection clamp assembly 7 FIG. 1. The assembly has a shoe 30 having parallel ridges 31 and 32 on a and an anvil 33 having parallel ridges 34, 35. The shoe and anvil have centerlines contained in a centerline plane 36 parallel to the plane 24, the ridges of the pressure shoe being equally spaced on either side of centerline plane as are the ridges 34 and35 of the anvil which is in afixed position rigidly secured to a frame member, not shown.

. For clarity of illustration, the shoe and anvil are shown at a scale different from that of the flitch, and particularly the ridges are exaggerated. Means are provided to apply a downward force 37 to the shoe, which force is resisted by an upward reaction 37-R compressing the flitch between the anvil and the shoe, the

ridges forming corresponding depressions in the upper and lower sides 13, 14 of the flitch as it is driven by the feed rolls to pass therebetween. Thus the depression form tracks which restrain travel of the flitch so that the flitch axis is coincident with the longitudinal axis roll pair 15, 16 and by a further feed roll pair, later particularized, spaced at a greater distance from the clamp than the roll pair 15, 16, hereinafter the second roll pair, the further roll pair being a first roll pair. Thus the flitch is, considering lateral deflection, efiectively a cantilever extending forward from the second roll pair and supported by the deflection clamp.

Means to eflect longitudinal travel of the flitch to the edge chipper are thus provided by a structure including the deflection clamp and the roll pairs, longitudinal travel being as above defined, viz meaning that the flitch axis and the cant axis are coincident with the iongitudinal axis, the travel being motion beingessentially pure translation within the tolerance as stated. Fee Roll and Clamp Linkage, FIGS. 6, a

FIG. 5, which is later described, shows mechanical details of the linkage, FIG. 6 being kinematic diagrams of the linkage. In FIG. 6 the roll pair l5, 16, which as before stated, is the second roll pair, is shown generally central of the linkage 8. The further roll pair mentioned above has an upper pressure roll 41 and a lower pressure roll 42, being the first roll pair and being spaced from the second roll pair so that a leading edge 45, FIG. 7 of the flitch 10 passes first between the first roll pair in travelling through the edger in the direction 9. An

outfeed roll pair having a pressure roll 43 and a fixedroll 44 is spaced from the deflection clamp at an outfeed end of the edge chipper, the outfeed pair receiving the flitch when it has passed through the chipper knives removing the waney edges to form the cant. The fixed rolls are parallel to the fixed roll 16, and are positioned in a horizontal plane so that the lower side 14 of the flitch bears against the roll in travelling through the chipper.

A link 46, being efl'ectively a bell crank, has an upper arm 47 and a lower arm 48, the bell crank being journailed on a horizontal transverse shaft 49. The pressure roll 41 is journalled at a lower end of the lower arm 48 of the bell crank. A trunion mounted fluid activated press roll cylinder 50 has a piston rod 51 an outer end of which is secured to the upper arm 47 as seen at 52, so that retraction of the piston rod rotates the bell crank 46 counterclockwise, as shown by a directional arrow 53, forcing the pressure roll 41 against the upper side 13 of the cant. i

The pressure roll 15 is journalled at a lower end of a similar bell crank 54, this bell crank being journalled on a shaft 55, and the pressure roll 43 of the outfeed pair is similarly mounted on a bell crank 56, journaled on a shaft 57.

An outer end of the upper arm 47 of the bell crank 46 is forked as seen at 58, bell cranks 54 and 56 are similarly forked as seen at 59 and 60, the forks being pressure shoe has effectively a bell crank action. The

movable crossheads are slidable longitudinally of the rod 61.

Thus retraction of the piston rod 51 rotating the bell crank 46 counterclockwise as shown by the arrow 53 moves the rod in a forward direction indicated by an arrow 68. An adjustable stop 69 is secured to the rod 61 bearing against the crosshead 63 engaging the bell crank 54. The stop 69 bears against a forward side of the crosshead 63 so that motion of the rod 61 in a direction opposite to that shown by the arrow 68 would cause the bell crank 54 to rotate lifting the pressure roll 15 away from the upper side 13 of the cant. Similarly positioned first adjustable stops 70 and 61 bearrespectively against forward sides of the crossheads 66 and 64.

A second adjustable stop 72 is spaced from a side of the crosshead 63 opposite the side against which the stops 69 bears. Similarly placed second adjustable stops 73 and 74 are provided for the crossheads 64 and 66. A resilient means 75 extends in compression between the stop 72 and the crosshead 63, similar resilient means 76 and 77 being provided between the crossheads 66 and 64 extending in compression respectively to the adjustable stops 73 and 74.

When the leading edge of the cant moving in the direction 9 is about to enter between the first feed roll pair 41, 42 the piston rod 51 of the press roll cylinder 50 can be extended so as to rotate the bell crank 46 in a direction opposite to that shown by the arrow 53, so lifting the pressure roll 41 to facilitate entry of the cant. When the leading edge is passed between the first press roll pair to attain a broken line position such as indicated at 45', the piston rod is retracted bringing the pressure roll in contact with the upper side and exerting such force as is required for effective drive. The stops can be adjusted so that the bell cranks 54 and 56 are in broken line positions indicated respectively at 54 and 56', with the pressure shoe 30 being in a broken line position 30'. In the broken outline positions the pressure rolls 15 and 43, and the pressure shoe 30, are, typically, from one quarter to one half an inch below the full line position shown in which these members are in contact with the upper side 13. The cant has a thickness T defined between its upper and lower sides, entry of the cant through the first feed roll pair senses the thickness T and automatically places the bell cranks 54 and 56, together with the pressure shoe 30, in their broken outline positions. It is seen that adjustment of the stops 69 and 71 can be made so that the pressure rolls 15 and 43 are, respectively, at determinate distances above the fixed rolls l6 and 44. Similarly, adjustment of the stop 70 can place the broken outline position 30' of the pressure shoe at a determinate distance from the anvil at 33 prior to entry of the leading edge.

When the leading edge of the cant is entering between the second roll pair, entry lifts the bell crank of the second roll pair from the broken outline position 54' to the full line position 54. Since the rod 61 is stationary, the crosshead 63 moves away from the stop 69 compressing the resilient means against the stop 72. The resilient means 75 has a force constant, thus force urging the pressure roll 15 downwards against the upper side 13 of the cant depends upon the force constant of the resilient means and the position of the adjustable stop 72, so with the pressure shoe 30 and the outfeed pressure roll 43.

The force constant of the resilient means being known, it is seen that the broken outline positions can be individually adjusted for a particular increase in separation, or lift distance, caused by the entering cant, and that in each case downward force is also independently adjustable. Magnitudes of the forces are obtained empirically. Once this is done it is seen that sensing of the thickness T by entry of the cant between the first feed roll pair passes information to the second pressure roll, to the pressure shoe, and to the outfeed pressure roll, so that each is automatically placed in a position for effective restraint and drive when the flitch enters.

The mechanism described and illustrated with reference to FIG. 6 is thus means, responsive to entry of the flitch between a first roll pair, automatically to place the succeeding roll pair or pairs, and the pressure shoe, in a determinate position for effective drive and restraint.

The bell cranks and the pressure shoe are described above as having forked upper ends. Kinematically, the upper arm 47 of the bell crank 46 of the first pressure roll pair, a portion 61.1 of the rod 61 extending from the upper end of the upper arm 47 to the fork of the bell crank of the second pressure pair, the (undesignated) upper arm of the bell crank 54, and a fixed link defined between the shaft 55 and 49 can be considered as links of a four-bar mechanism. So considered pin joints can be substituted for the forks. There are two further four-bar mechanisms similarly defined the rod 61 being common to each, and the upper arms of the bell cranks (including the shoe) being common to adjacent four-bar mechanism.

lfthe rod 61 be restrained so as to be capable only of motion of translation, the linkages are not four-bar mechanisms. Such restraint adds rigidity considering the bar as a long column, rigidity is not however a problem in an edge chipper. Hence the rod, as exemplified, is not so restrained.

It is clear that, to provide required adjustment range, the common adjacent arms are not of equal lengths excepting in particular adjustment positions. Consequently pin jointing cannot be substituted throughout for the forks if the rod is continuous as described. There are four crossheads, pin joints can be used in lieu of forks at any two crossheads, thus defining one true four-bar mechanism. Forks or equivalent structure used at the two crossheads then remaining,adjustments can be effected as described.

Note that the trains are force closed by the resilient means and by the pressure roll cylinder, consequently lost motion which, otherwise, might arise at the forks is not a problem. Whether pin jointed or forked, upper ends of the bell cranks engage the crossheads so that either a true four bar mechanism or equivalent thereof, is defined.

FIG. 5

In FIG. 5 the edge chipper 6 is shown in perspective with outer coverings removed. Sensing mechanism is designated generally 100 being carried by a rigid frame 101.

In the bell crank 46 of the first infeed roll, the upper arm 47 has, two parts, viz parallel arms 102 and 103, the piston rod being secured to the arm 102 as shown, an end of the portion 61.1 of the rod 61 being pin jointed to an outer end of the arm 103 at 104. The crosshead 63 is also efl'ectively pin jointed to the bell crank 54, forming the before mentioned four-bar mechanism, one link of which, namely the rod portion 61.1 is of adjustable length. I

The rod 61 is not restrained for motion of translation, thus the crosshead 66 of the pressure shoe, and the crosshead 64 of the out feed roll bell crank 56, are

forked as described with reference to FIG. 6.

In FIG. 5 the resilient means 75, 76, 77 are compression springs, adjustment being effected as described with reference to FIG. 6.

In large edge chippers according to the present invention, producing cants having a width in excess of say about 18 inches, compression spring resilient means become unwieldy in size, and are difficult to adjust. FIG. 8

In these circumstances, pneumatic resilient means exemplified in FIG. 8 reduce these difficulties, particularly providing ease of adjustment.

An upper crank 110 engages a crosshead 111 of the rod 61, the croshead being secured by lock nut means 112 and 113. A double acting pneumatic cylinder 115 v has a piston rod 116 pin jointed to an upper end of the pressure shoe 30, the cylinder being effectively trunion mounted to the crank 110 at 117, control means 118 admit supply air under pressure to the cylinder.

Movementof the rod 61 rotates the crank 110 so that, with equal air pressures on each side of a piston of the pressure cylinder 115, the pressure shoe 30 rotates about the shaft 67 with movement of the rod 61 so as to provide a required lift, sensing being as before described. With the equal pressures on both sides of the piston being large, the downward force 37 which is developed by the cant lifting the pressure shoe, is correspondingly large. With the equal pressures smaller, the force 37 is correspondingly smaller.

To adjust lift, considering the crank 110 to be stationary, unequal pressures on each side of the piston extend or retract the piston rod 116. When the required lift is thus attained, pressures are equalized.

It is thus seen that structure above including the pneumatic cylinder resilient means is functionally equivalent that described above with reference to FIGS. 5 and '6. The four bar mechanism lacks as adjustable length link, its function being effected by the pneumatic means described.

I FIGS. 9, 10, 11 Pressure Shoe Details The pressure shoe 30 has a blade 121 having an upper end 122 adapted for engagement with the crosshead 66 FIGS. 5 and 6, and has has a lower side edge 123 which is disposed as seen in FIGS. 5 and 8.

The shoe is secured to the shaft 67, FIGS. 6 and 5, in a bore 124 in a boss of the blade. A curved shoe element 125, shown in detail in FIG. is obviously secured to the blade at an end remote from the bore 124, as shown.

As before stated, the curved shoe element 125 has peripheral ridges of which only the ridge 31 is seen in FIG. 10. FIG. 11 is a detail, at enlarged scale, showing shape of the peripheral ridge 31. The ridge is of trun-- cated triangular section, and is set in from an adjacent edge of the blade as shown. Referring to the truncated triangular section, typicaldimensions are as follows;

height one-sixteenth of an inch, truncated width one-sixteenth of an inch, sides sloping at 15 Anvil Details FIGS. 12, l3, 14

FIG. 12 is a side elevation of the anvil, FIG. 13 is a partly sectioned end elevation, and FIG. 14 is an enlarged scale detail of one ridge of the anvil.

The 'anvil 33 has a horizontal base plate 131 againstwhich the lower side 14 of the cant is disposed see FIG. 4 and a vertical securing plate 132 having slots 133 accepting bolts 134, FIG. 8 only, for securing the anvil to the frame.

At least one ridge 34 is provided on an upper side 135 of the base plate 131, the ridge or ridges being disposed generally vertically below the ridges of the curved shoe element 125 so that the reaction 37-R acts cutter heads appears as a straight line 183 joining the axes 25 and 26 of the rotating cutter heads, which-axes are here considered being vertical.

An extreme condition is shown where the cutter 182 is cutting to a large depth, and the cutter 181 is cutting to zero depth. Forces exerted by the rotating knives on the moving flitch are complex, but can be resolved into a radial component 187-r and a tangential component 1874. These forces have a resultant 187-R. Depth of cut varies in a random manner as do certain other 6 parameters affecting magnitude and direction of the resultant 187-R, however as depth of cut of the head 182 approaches zero, the resultant 187-R approaches zero in magnitude, and parallelism to the plane 183 in direction. Consequently the reaction has a range of position between 183 and 187-R, a broken line force vector 188-A representing an average condition.

For conditions shown in FIG. 7, the average l88-A intersects the deflection clamp at a distance D from the line 183, being spaced the distance D towards the in- I feed rolls, that is to say, in a direction opposite to the direction of travel 9.

Referring now to FIG. 7-A which is at a scale smaller than that of FIG. 7, and considering the leading edge 45 of the cant to be in a position adjacent to the plane 183,

the pressure rolls 41 and 15 of the first and second infeed roll pairs provide restraint against deflection of the flitch in a horizontal plane. Thus the flitch is effectively a cantilever having an inner end secured by the first and second feed roll pairs, and extending outwards from the second feed roll pair in the direction of travel. The average force vector 188-A has a component 188- D parallel to the plane 183 (which component is shown in FIG. 7-A only) and would, if no restraint were applied, result in a deflection of the cant which, as has been shown, is effectively a cantilever. In the present discussion the concern is deflection, and a component of the force 188-A parallel to the longitudinal axis 17 is disregarded. It is clear that if a restraining force 189 is applied by the deflection clamp 7, indicated in broken outline in FIG. 7-A, equal to and aligned with the component 188-D, deflection is zero. This is an ideal condition, which, in practice, can only occur momentarily.

As best seen in FIG. 1, an inner endof the anvil 33 of the deflection clamp extends nearly to the second feed roll pair, and an outer end extends beyond the plane 183. It is found in practice that spacing of the line of contact (actually a'narrow area of contact) of the pressure shoe from the plane 183 by the distance D and, providing an anvil having length as above, restraint applied by the clamp is such as to reduce deflection to within the tolerance.

By making D sufficiently large, it can be arranged that the flitch is engaged by the deflection clamp before reaching the cutter knives, that is to say before the force l87-R arises. In these circumstances the cantilever is supported close to an outer end bythe deflection clamp, and other things being equal any deflection then arising would be less than an unsupported cantilever. Thus, in certain kinds of edgers, the first feed roll pair can-be omitted, so that the cantilever becomes effectively a simple beam.

In either case, i.e. with one or with two infeed roll pairs, when the leading edge 45 of the cant passes between the outfeed rolls, any deflections are further reduced. In practice it is found that using two infeed roll pairs, the deflection clamp being placed close to one side of the flitch so that the chipper can accommodate flitches having a large range in width as has been explained, a value of D of about an inch or two is satisfactory. It is seen that 'D'is not critical but that better restraint is provided when the deflection clamp is spaced somewhat away from the plane '183'towards the second infeed roll pair.

The axes 25 and 26 have been considered as being vertical, in practice the axes are parallel and co-planar with the plane 183 being inclined to the vertical by, typically, some 15.

FIG. 7 can, in these circumstances be considered as being a projection upon a horizontal plane mid-way between the flitch upper and lower sides, in which case the paths of the cutter knives would appear elliptical.

In further reference to deflection magnitude, it is evident that when the flitch is engaged by the infeed and outfeed roll pairs deflection is less than when one end is not so engaged --as when the leading edge is entering and when a following edge has passed through the second infeed roll pair. Thus any cant irregularity due to deflection is somewhat larger at the ends of the cant a condition which, ordinarily, is within tolerance. In the exemplifications, the chipper head axes 25, 26, FIG. 3 are vertical or can be inclined, a head with chipper knives being envisaged. Other chipper means for use in side edgers are known, all rotate and can be considered as having a rotating head. Regardless of the chipper means used in trimming irregular waney edges forces such as l88-Dv FIG. 7-A

arise, and are resisted as indicatedat 189 by reaction at 'thetracks.

We claim:

1. Side .edgechipper apparatus for chipping waney edges (11,12) of a flitch (.10)having parallel upper and lower sides'('13, .14), chipping of the edges producing a cant'having side edges 22, 23)'parallel'to a common longitudinal axis of the flitch and cant, the apparatus including:

a. at least one, viz. a first, infeed roll pair (15, 16),

"b. at least one outfeed'roll pair having a pressure roll (43) and afixed roll (44),

c. a rotating cutter head (182) disposed between the infeed andoutfeed rolls, adapted for-the flitch to be drivenby the infeed roll pair to'travel toand through the outfeed roll pair so that the cutter head chips a waneyedge producing a .cant side dg d. an anvil (33) fixed in a:position'to bear against the lower-side of-the'flitch,

e. the anvil having at least one ridge (34),

f. apressure shoe (30)-bearing against the upper side of-the flitch, the pressure shoe having at least one ridge (32),

g. means to apply a force'(37) to the pressure shoe urging it against the upper side-of the flitch with the ridge bearing against the upper side,

so thatasthe flitch travels as aforesaid being urged by the force against theanvil, depressions are made bythe ridges -in the upper .and lower sides forming tracks restraining the travel of .the flitch to longitudinal motion of pure translation .of the common longitudinal axes.

2. Apparatus as definedin claim 1, and

h. means responsive to entry of the flitch between the first infeed roll pair to place the outfeed roll pair and the shoe ina determinate position for effective drive and restraint.

3. Apparatus as defined in claim 2, wherein the means (h)..includes:

i. a four bar mechanism having a link (16.1) of variable length and means to alterits length, a link of fixed length and opposite first and second bell crank links,

a pressure 'roll of the .firstzinfeed roll pair being journalled at alower endof the first bell crank link, means (50) to apply a downwardforce to the pressure'roll urging itagainst the upper side of the flitch, thelower sidebearingxupon a fixed roll of the pair, the upper and lower pairs then being spaced by a distance determined by thickness of the cant,

constructed and arranged so that, the pressure shoe being the second opposite bell crank link, alteration of the length of the variable length link spaces the shoe above the anvil at distance determined by the .thickness of the cant and the adjusted length of the variable link, the distance being less than the flitch thickness by a lift distance, with entry of the flitch between the pressure shoe and the anvil lilting the pressure shoe through the lift distance,

4. Apparatus as defined in claim 3, wherein the means (h)'further includes:

iv. a first adjustable stop (70) slidable of the link of variable length and adjacent the pressure shoe,

v. a secondadjustable stop (73) slidable of the said link, the adjustable stops being spaced from one another, I

vi. a crosshead (66) between the stops the crosshead being slidable of the said link, an upper end of the second bell crank engaging the crosshead,

vii. the resilient means being a spring (76) extending in compression between the second adjustable stop and the crosshead urging the crosshead against the first adjustable stop with a force depending upon the spacing between the stops,

the length .of the'adjustable link and hence 'thelift distance being determined by position of the first adjustable stop, magnitude of the force urging the pressure shoe as aforesaid being, for a particular position of the first stop, determined by'the spacing of the second stop from the first stop.

5. Apparatus as defined in claim 4, wherein means (h) is still further characterized by:

viii. afurther four-bar mechanism having a link of adjustable length, opposite second and third (56) bell crank links, the second bell crank link being common to both mechanisms, and a fixed link,

ix. a pressure roll (43) of the outfeed roll pair being joumalled at a lower end of the third bell crank link,

x. the adjustable link of the further four-bar mechanism having spaced first and second adjustable stops (71,74) and a moveable crosshead (64) with a spring (77) extending in tension between the the crosshead and the second adjustable stop,

' xi. an upper end of the third bell crank link engaging the crosshead, adapted for alteration of the length of the adjustable link to space the pressure roll of the outfeed roll pair above the fixed roll by a distance equal to the cant thickness less a determinate adjustable left distance and, for a particular lift distance and position of the first stop, for the spacing of the second stop from the first stop to determine the force with which the pressure roll is urged against the cant passing between the outfeed roll pair.

6. Apparatus as defined in claim 1, having pneumatic means applying the force to the pressure shoe.

7. Apparatus as definedin claim 2, wherein the 7 means (h) includes,

- xiii. an upper crank (110) of the second bell crank engaging a crosshead (111) of the link opposite the fixed link, a double acting pneumatic cylinder (115) having a piston rod (116) pin jointed to an upper end of the pressure shoe (30), the cylinder being eflectively trunnion mounted (117) to the crank, xiv. means selectively to admitair under pressure to one side of a piston of the cylinder causing the piston rod to extend so as to move the pressure shoe away from the anvil; to admit air under presof the cylind r t retract s e 0 an o 't sid ui piston r urging the shoe towar s t e and; and to admit air at equal pressures to each side of the piston, which equal pressures are of determinate magnitude, constructed and arranged so that, with'the fiitch just having entered between the first infeed roll pair, the

shoe can be spaced a determinate distance from the anvil which distance is vflitch thickness less a lift distance; with entry of the fiitch betweenthe pressure shoe and the anvil lifting the shoe through the lift distance and developing a force between the shoe and the fiitch of determinate magnitude according to the magnatude of the equal pressures on each side of the piston.

8. Apparatus as defined in claim 5, further including; a second infeed roll pair having a pressure roll and a fixed roll, the rotating cutter head being disposed between the second infeed roll pair and the outfeed rolls; means responsive to entry of the fiitch between the first roll pair to place the pressure roll of the second infeed roll pair at a distance from the fixed roll equal to the fiitch thickness less a lift distance; and adjustable resilient means urging the'pressure roll towards the fixed roll; so that the flitch entering between the rolls of the second roll pair moves lifts the pressure roll through the lift distance with the pressure roll being urged against the fiitch with a force determined by adjustment of the resilient means.

9. Apparatus as defined in claim 8, wherein the anvil is spaced an inch or two from an axis of the cutter head towards the infeed roll pair.

i t IF t 

1. Side edge chipper apparatus for chipping waney edges (11,12) of a flitch (10) having parallel upper and lower sides (13, 14), chipping of the edges producing a cant having side edges (22, 23) parallel to a common longitudinal axis of the flitch and cant, the apparatus including: a. at least one, viz. a first, infeed roll pair (15, 16), b. at least one outfeed roll pair having a pressure roll (43) and a fixed roll (44), c. a rotating cutter head (182) disposed between the infeed and outfeed rolls, adapted for the flitch to be driven by the infeed roll pair to travel to and through the outfeed roll pair so that the cutter head chips a waney edge producing a cant side edge, d. an anvil (33) fixed in a position to bear against the lower side of the flitch, e. the anvil having at least one ridge (34), f. a pressure shoe (30) bearing against the upper side of the flitch, the pressure shoe having at least one ridge (32), g. means to apply a force (37) to the pressure shoe urging it against the upper side of the flitch with the ridge bearing against the upper side, so that as the flitch travels as aforesaid being urged by the force against the anvil, depressions are made by the ridges in the upper and lower sides forming tracks restraining the travel of the flitch to longitudinal motion of pure translation of the common longitudinal axes.
 2. Apparatus as defined in claim 1, and h. means responsive to entry of the flitch between the first infeed roll pair to place the outfeed roll pair and the shoe in a determinate position for effective drive and restraint.
 3. Apparatus as defined in claim 2, wherein the means (h) includes: i. a four bar mechanism having a link (16.1) of variable length and means to alter its length, a link of fixed length and opposite first and second bell crank links, ii. a pressure roll of the first infeed roll pair being journalled at a lower end of the first bell crank link, means (50) to apply a downward force to the pressure roll urging it against the upper side of the flitch, the lower side bearing upon a fixed roll of the pair, the upper and lower pairs then being spaced by a distance determined by thickness of the cant, constructed and arranged so that, the pressure shoe being the second opposite bell crank link, alteration of the length of the variable length link spaces the shoe above the anvil at distance determined by the thickness of the cant and the adjusted length of the variable link, the distance being less than the flitch thickness by a lift distance, with entry of the flitch between the pressure shoe and the anvil lifting the pressure shoe through the lift distance, iii. resilient means (e.g. 76) responsive to lift of the pressure shoe applying the force (37) urging the pressure shoe against the upper surface of the flitch so as to compress it against the anvil.
 4. Apparatus as defined in claim 3, wherein the means (h) further includes: iv. a first adjustable stop (70) slidable of the link of variable length and adjacent the pressure shoe, v. a second adjustable stop (73) slidable of the said link, the adjustable stops being spaced from one another, vi. a crosshead (66) between the stops the crosshead being slidable of the said link, an upper end of the second bell crank engaging the crosshead, vii. the resilient means being a spring (76) extending in compression between the second adjustable stop and the crosshead urging the crosshead against the first adjustable stop with a force depending upon the spacing between the stops, the length of the adjustable link and hence the lift distance being determined by position of the first adjustable stop, magnitude of the force urging the pressure shoe as aforesaid being, for a particular position of the first stop, determined by the spacing of the second stop from the first stop.
 5. Apparatus as defined in claim 4, wherein means (h) is still further characterized by: viii. a further four-bar mechanism having a link of adjustable length, opposite second anD third (56) bell crank links, the second bell crank link being common to both mechanisms, and a fixed link, ix. a pressure roll (43) of the outfeed roll pair being journalled at a lower end of the third bell crank link, x. the adjustable link of the further four-bar mechanism having spaced first and second adjustable stops (71, 74) and a moveable crosshead (64) with a spring (77) extending in tension between the the crosshead and the second adjustable stop, xi. an upper end of the third bell crank link engaging the crosshead, adapted for alteration of the length of the adjustable link to space the pressure roll of the outfeed roll pair above the fixed roll by a distance equal to the cant thickness less a determinate adjustable left distance and, for a particular lift distance and position of the first stop, for the spacing of the second stop from the first stop to determine the force with which the pressure roll is urged against the cant passing between the outfeed roll pair.
 6. Apparatus as defined in claim 1, having pneumatic means applying the force to the pressure shoe.
 7. Apparatus as defined in claim 2, wherein the means (h) includes, xii. a four bar mechanism having a fixed link, a link (61) opposite thereto, and opposite first and second bell crank links, xiii. an upper crank (110) of the second bell crank engaging a crosshead (111) of the link opposite the fixed link, a double acting pneumatic cylinder (115) having a piston rod (116) pin jointed to an upper end of the pressure shoe (30), the cylinder being effectively trunnion mounted (117) to the crank, xiv. means selectively to admit air under pressure to one side of a piston of the cylinder causing the piston rod to extend so as to move the pressure shoe away from the anvil; to admit air under pressure to an opposite side of the cylinder to retract the piston rod urging the shoe towards the anvil; and to admit air at equal pressures to each side of the piston, which equal pressures are of determinate magnitude, constructed and arranged so that, with the flitch just having entered between the first infeed roll pair, the shoe can be spaced a determinate distance from the anvil which distance is flitch thickness less a lift distance; with entry of the flitch between the pressure shoe and the anvil lifting the shoe through the lift distance and developing a force between the shoe and the flitch of determinate magnitude according to the magnatude of the equal pressures on each side of the piston.
 8. Apparatus as defined in claim 5, further including; a second infeed roll pair having a pressure roll and a fixed roll, the rotating cutter head being disposed between the second infeed roll pair and the outfeed rolls; means responsive to entry of the flitch between the first roll pair to place the pressure roll of the second infeed roll pair at a distance from the fixed roll equal to the flitch thickness less a lift distance; and adjustable resilient means urging the pressure roll towards the fixed roll; so that the flitch entering between the rolls of the second roll pair moves lifts the pressure roll through the lift distance with the pressure roll being urged against the flitch with a force determined by adjustment of the resilient means.
 9. Apparatus as defined in claim 8, wherein the anvil is spaced an inch or two from an axis of the cutter head towards the infeed roll pair. 